Nitrous oxide anneal of TEOS/ozone CVD for improved gapfill

Abstract

A method of filling a gap defined by adjacent raised features on a substrate includes providing a flow of a silicon-containing processing gas to a chamber housing the substrate and providing a flow of an oxidizing gas to the chamber. The method also includes depositing a first portion of a film as a substantially conformal layer in the gap by causing a reaction between the silicon-containing processing gas and the oxidizing gas. Depositing the conformal layer includes varying over time a ratio of the (silicon-containing processing gas):(oxidizing gas) and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the conformal layer. The method also includes depositing a second portion of the film as a bulk layer. Depositing a second portion of the film includes maintaining the ratio of the (silicon-containing processing gas):(oxidizing gas) substantially constant throughout deposition of the bulk layer and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the bulk layer. The method also includes exposing the substrate to nitrous oxide at a temperature less than about 900° C. to anneal the deposited film.

1. A method of filling a gap defined by adjacent raised features on a substrate, comprising:
 providing a flow of a silicon-containing processing gas to a chamber housing the substrate; 
 providing a flow of an oxidizing gas to the chamber; 
 depositing a first portion of a film as a substantially conformal layer in the gap by causing a reaction between the silicon-containing processing gas and the oxidizing gas, wherein depositing the conformal layer comprises varying over time a ratio of the (silicon-containing processing gas):(oxidizing gas) and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the conformal layer; 
 thereafter, depositing a second portion of the film as a bulk layer, wherein depositing a second portion of the film comprises maintaining the ratio of the (silicon-containing processing gas):(oxidizing gas) substantially constant throughout deposition of the bulk layer and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the bulk layer; and 
 thereafter, exposing the substrate to nitrous oxide at a temperature less than about 900° C. to anneal the deposited film. 
 
   
   
     2. The method of  claim 1 , wherein exposing the substrate to nitrous oxide at a temperature less than about 900° C. to anneal the deposited film comprises exposing the substrate to nitrous oxide at a temperature less than about 750° C. to anneal the deposited film. 
   
   
     3. The method of  claim 1 , further comprising thereafter planarizing the film. 
   
   
     4. The method of  claim 3 , wherein planarizing the film comprises subjecting the film to chemical mechanical polishing. 
   
   
     5. A method of forming isolation structures in a silicon substrate, comprising:
 etching trenches in the substrate; 
 providing a flow of a silicon-containing processing gas to a chamber housing the substrate; 
 providing a flow of an oxidizing gas to the chamber; 
 causing a reaction between the silicon-containing processing gas and the oxidizing processing gas to form a silicon oxide layer at least in part by;
 depositing a first portion of a film as a substantially conformal layer in the trenches by causing a reaction between the silicon-containing processing gas and the oxidizing gas, wherein depositing the conformal layer comprises varying over time a ratio of the (silicon-containing processing gas):(oxidizing gas) and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the conformal layer; and 
 thereafter, depositing a second portion of the film as a bulk layer, wherein depositing a second portion of the film comprises maintaining the ratio of the (silicon-containing processing gas):(oxidizing gas) substantially constant throughout deposition of the bulk layer and regulating the chamber to a pressure in a range from about 200 torr to about 760 torr throughout deposition of the bulk layer; 
 
 heating the substrate in the presence of nitrous oxide; and 
 thereafter, planarizing the layer. 
 
   
   
     6. The method of  claim 5 , wherein planarizing the layer comprises subjecting the layer to chemical mechanical polishing. 
   
   
     7. The method of  claim 5 , wherein heating the substrate in the presence of nitrous oxide comprises exposing the substrate to nitrous oxide at a temperature less than about 900° C. to anneal the deposited film.